Today we're going to point our skeptical eye at one of the most popular marketing gimmicks from the past few years: the sales of products and services with the claim that they will "boost your immune system". It sounds simple and desirable. Who wouldn't want a superpowered immune system capable of fighting off anything from a cold to cancer? Is such an ability really something you can buy in a bottle?

It's an easy claim to sell to people, because it's so clear and seems to make such obvious logical sense. The stronger your immune system, the greater its ability to fight disease. It sounds like it should be just like building muscle: A stronger bodybuilder can lift heavier weights, and a boosted immune system can fight off stronger diseases. Doesn't that sound right?

It may, but it's a completely invalid analogy. A healthy immune system is more accurately represented by a balanced teeter totter. If your immune system is compromised or otherwise weakened, one side of the teeter totter sags, and your body becomes more easily susceptible to infection. Conversely, if your immune system is overactive, the other side of the teeter totter sags, and the immune system attacks your own healthy tissues. This is what we call an autoimmune disease. Conditions like lupus, rheumatoid arthritis, psoriasis, and multiple sclerosis are all autoimmune diseases caused by "boosted", or overactive, immune systems. You're at your healthiest when the teeter totter of your immune system is balanced right in the center; neither too weak, nor too strong.

If you could boost your immune system, it would automatically and immediately be harmful.

So what do these companies mean when they claim their products boost the immune system? Fortunately for your body, they generally mean nothing at all. In recent years, the Federal Trade Commission and the Food and Drug Administration has been trying to crack down on products making unsubstantiated health claims, such as boosting the immune system. This is difficult for a number of reasons. First, "boosting your immune system" is medically meaningless; there is no such thing, so the assertion does not constitute a medical claim all by itself. You may recall that the supplement product Airborne was fined by the FTC and ordered to refund the money of everyone who had ever bought their product, but this was only because they went farther and specifically claimed their product could treat and prevent colds. Second, regulators are hopelessly outnumbered by the hordes of mail order and Internet businesses that can literally pop up overnight, to say nothing of the many well established companies like Airborne. Third, it's a very simple matter for such companies to subtly change their wording to make it even less specific, and thus escape prosecution. Today it's popular for products to say they "support a healthy immune system", and so they do, in the same way that any food or even breathing keeps your body alive and thus "supports" all its functions. They could just as honestly say their product supports body odor and aging.

Up until about ten years ago, nobody had invented the marketing term yet, so nobody ever thought to buy special supplements or specially grown produce to boost their immunity. Without such products, one wonders how the human race could have survived hundreds of thousands of years. Or even the 1980s or 1990s. Were we really less healthy then? Did we all truly have compromised immune systems?

You see, health is not the result of a superpowered immune system. Health is simply the absence of disease. Good health is the baseline. You can't be healthier than baseline. Once you're at the baseline, anything that happens to your immune system in either direction is bad. For a person in good health, who watches their diet and exercises, to walk into a smoothie store and order the special immunity boosting supplement, would be harmful to their health. Would be, if that supplement actually did anything.

It would be easy for companies to demonstrate that their products work as advertised. The immune system is a surprisingly complex collection of structures and processes throughout the body. Many of these are types of cells that can be found in the blood. If a product actually boosted your immune system, it would have to increase the counts of one or more of these cell types. That's something that we could measure directly, and prove or disprove the claim. The problem with doing such a test is that it would be unethical, since you would have to give someone an imbalance likely to result in an autoimmune disease.

Let's take a quick look at what some of these systems are:

The most obvious parts of your immune system are the external physical barriers: Your skin, saliva, tears, and processes such as coughing and sneezing. When we catch a cold, our immune system responds by increasing production of all of these responses. It's not the cold that gives you a running nose and makes you cough and sneeze, that's your immune system. Do you really want to boost that and walk around sneezing and drooling? Because that's what a "boosted" immune system means.

Inflammation is another important immune response. Damaged cells release several types of triggering molecules that do such things as attract leukocytes or tell your body's blood vessels to dilate. These molecules can also hamper protein synthesis, which is intended to harm any viruses nearby that might have caused the damage. Inflammation is not a good thing. It's like a fireman spraying water on your house. You do it when you have to, you absolutely do not want to artifically stimulate inflammation when you don't have to.

White blood cells, or leukocytes, are what most people think of when they hear "immune system". But what many people don't know is that there are many different types of leukocytes, not just those in our blood, but also other types in most of our other tissues as well. Leukocytes include macrophages, neutrophils, dendritic cells, mast cells, killer cells, and basophils, and others, all of which do different things.

All of those systems together comprise our "innate" immune systems, and they're just the half of it. We also have "adaptive" immune systems, and these are the systems that react to specific pathogens, multiply, and then become long-term guards against a recurrence of that same pathogen, becoming a sort of "memory" for your immune system. The adaptive immune system grows every time you challenge it with a specific germ, and it's also what reacts to a vaccine and becomes a prophylactic against a specific disease. The adaptive immune system is made up of special cells called lymphocytes, which include:

Killer T cells, which do the dirty work, binding to and killing cells that match their specific receptor. Each killer T cell recognizes only one specific antigen, so we all have many, many, many different populations of killer T cells.

Helper T cells are those which recognize pathogens, and express new T cell receptors for the killer T cells; in effect, creating new types of killer T cells designed to fight that specific pathogen.

γδ (gamma delta) T cells perform a function similar to helper T cells, but are not necessarily triggered by new pathogens. Their function is pretty complex.

B cells come between pathogens and helper T cells. They have a vast array of receptor proteins on their surfaces, and when a pathogen binds to one, the B cell divides millions of times. Each copy then finds a helper T cell to transfer the information about the new pathogen to killer T cells.

Those are the major components, but believe me, I've just given you an oversimplified 30,000-foot view of the immune system. Both halves, the innate and the adaptive, are comprised of many different components. Some act in concert, some act independently. There are many, many different ways in which parts of your immune system can be compromised, and addressing each of these deficiencies requires a different strategy. The notion that a single juice drink or supplement pill can "boost your immune system" is — to borrow a phrase — "so wrong it's not even wrong".

Since the function of the adaptive immune system is to react to challenges and develop new defenses, it can indeed be improved. Every time you catch a cold or get vaccinated, your adaptive immune system builds a new army of killer T cells ready to fight off a future recurrence of the same pathogen. There is no nutritional supplement, superfood, or mind/body/spirit technique that will do this for you. Those B cells only know which proteins to express by being attacked by specific disease agents.

The usual response that I hear to these arguments is that "immune boosting" products are simply trying to restore healthy immune function, since we're all walking around with compromised immune systems, because we eat badly and are obese and live in a toxic world. This is a familiar argument, and it's also easy to sell. It sounds like it makes sense. People do overeat, we love our prepared foods, and few of us take any special interest in the chemicals making up the objects in our daily lives. Has this truly resulted in compromised immune systems?

In fact, the opposite is true. Obese people generally have inflammation, which is an immune response. We catch colds and have no difficulty in producing symptoms. When we're exposed to irritating substances, we react with hives or itching or asthma, all of which are immune responses. Practically every one of us has some immune system response going on right now. The claim that living in our modern world has compromised our immune systems is measurably, and unambiguously, untrue.

There are real conditions in which immune systems can be compromised. These include primary immunodeficiencies, which are usually genetic and exist from birth, and require complex medical intervention; and acquired immunodeficiencies, usually resulting from disease, like AIDS, some cancers, even chemotherapy. A specific component of the immune system is affected and requires a specific treatment. Acquired immunodeficiency can result from malnutrition, but you have to be practically starving to death. It's the opposite problem from eating too many cheeseburgers.

Supplements, juices, or any products that claim to "boost your immune system" are frauds. They are for-profit solutions to a problem that does not exist and was invented by clever marketers to scare you into buying the products. Don't stand for anyone telling you that your balanced teeter totter can be brought into better balance by piling sandbags on one end.